Rich asks:
I have a 12 ¾ x 12 ¾ x 12 ¾ ECT44 C box with a 4 cell ECT32 C Partition inside. It holds 4 1 gallon jugs. Customer is asking what the compression strength is of the finished box and how high they can stack. I used to go by Rule 41 and say ECT44 is rated for 85 pounds and if the 4 jugs weigh 40 pounds the bottom box can only support two rows high. Am I correct?
You need to use the McKee formula to determine the stacking strength/compression potential of the corrugated box. We need to assume that you retained a minimum 44 ECT and that the final board caliper was 0.166 inches. We also assume good converting processes so that the scores and slots are proper manufactured and that the box was glued adequately and squarely. If all of the above have been met, the initial compression strength of the box should be 750 pounds. Add to this the 32 C four open cell partition and you have the workings of a corrugated container able to initially support around 1100 pounds.
You must then factor all this by the degradation factors of pallet deck board spacing, pallet stacking patterns, humidity, and storage time. All these are given on page 3.13 of the FBA Handbook.
— Ralph